Power razor



w. P. BOYD 2,375,.521

May 8, 194 5.

POWER RAZOR Fi led Afig. 11, 1938 7/- WK ATTORNEY I Patented 1-945 I UNITED STATES PATElilT OFFICE;

POWER. RAZOR William P. Boyd,.Nashua, N. 11.; Roland a. numham, administrator of said William P.-Boyd,

deceased, assignor of one-half to Gardner W. 2..

. Pear-son, Lowell, Mass.

P. Boyd, Exeter, N. H.

, and one-half to Mary Application August 11, 1938, Serial No. 22'4,3o'1 13 Claims. (c1. 30 43) This inventionrelates to power operated safe-- ty razors for use in shaving.

I am aware that there are devices in which there is a protecting shield with perforations into which the short hairs enter and inside such a 7 cases, it has a cutting edge which shears along theinside of the guard, cutting the hair by the sharp edge of a blade. In this device, I use a guard which is a perforated tube fixed to and' carried at one end by a housing. A blade holder is revolved inside this tubular guard by a shaft also carried by the housing and driven by power. The power may be provided by an electric motor carried by the housing or in any other way, such as by a flexible power shaft.

This bla'de holder has one or more longitudinal slots arranged in a plane. or planes which may pass through, but preferably a short distance from the axis, so that they rake forward in the direction of rotation.

The blade holder may conveniently be cylindrical and may or may not have a bearing at the free end of the tubular guard.

Instead of a cylindrical blade holder with slots, I can use flat surfaces in planes similar to those just described to one or more of each of which a cutting blade i -slidably attached. I so attach the blades by formingslots in them and attaching each by headed screws or pins to a flat surface.

The mainprinciple of my device is the utilization of one or more longitudinal blades which are so carried by a revoluble blade holder that, as

Besides cutting the hair, the great advantage of this construction is that each blade will last for a very long time, during which time it does not need to be sharpened. The device, therefore, is always instantly ready for use with no delay for replacing or sharpening blades.

'It is preferably used dry and with no lather or shaving cream.

-In the drawing,

Fig. 1 is a side elevation of a complete power razor of my construction with parts broken away to show the interior construction.

Fig. 2 is an enlarged elevation of the outside of the cap shown in Fig. l.

- Fig. 3 is an enlarged sectional view as from the left of line 3-3 of Fig. 1 but showing also the human flesh and hairs-as they appear when the device is operating.

Fig. 4 is an enlarged vertical longitudinal section of the outer end of the device, as shown in Fig. 1. r

Fig. 5 is a view similar to Fig. 3 showing a slight modification of.the arrangement of a cutthey revolve, centrifugal force throws the blades ting blade and slot.

Fig. 6 is a view similar to Figs. 3 and 5, showing a modification of the blade holder in which there are no slots.

Fig. '1 is a detail sectional view looking mine 1' direction of the arrow on the line 1-1 of Fig. 6. Fig. 8 is an elevation, with parts broken away and diagrammatic, showing another method of applying power.

Fig. 9 is a vertical longitudinal sectional view T represents a tubular guard which 'is fixed to housing H and which has an interior cylindrical surface I and an outside surface 2, there being a flat space 3 on' the outside surface. 4, 4 repre-' sent a plurality of perforations or hair holes which extend through the wall of the guard.

' Preferably these are of truncated conical form,

being larger at the outside than they are at the inside so that there is at the edge 5 of each, at the'interior cylindrical surface I, a relatively sharp edge.

The axis of revolution of the motor I! and the shaft Scarried thereby coincide with the axis oi the inside cylindrical surface I of guard 'r.

This shaft S carries a blade holder A which may be cylindrical, or of other suitable shape, preferi ably so made that its parts will properly balance when revolved at a high rate of speed by the motor l2.

As shown in Figs. 1 to 3, the blade 1 holder, such as A, is provided with a plurality of ldngitudinal slots 30 and 31 J from the axis with reference to the direction of which rake forward rotation. The sides of these slots, as shown, are parallel and, as shown in Figs. 1 to 3, the planes l of their surfaces extended would be parallel with v 1 the axis of rotation.

3 blade should rake slightly, as shownin Fig, 3, so

The outer edge, such as 36, of each cuttin that its forward edge 31, co-operating with the i inner cutting edge 5 of eachperforation or hair hole 4 will make a clean cut of each hair of the 1 human beard which projects into each perforation; Whatever shape this edge takes in the beginning, it will gradually wear down so that it 1 end 29.

1 will slip along on the inside surface I and the 1 cutting edge 31 will always remain sharp.

For convenience in assembling and cleaning,

Asshown, each slot or 3| terminates at 32 1 or 33 atv the housing end and at 34 or 33 at the 5 free end in a dead end. Each slot should be of 5 such a length and width that a blade B can slide with a smooth, running fit and each slot is of such depth that its blade B will be held firmly but slidably. Each blade B is of rectangular form in length and height or depth and may be of substantial thickness, such ofaninch.

as one-sixteenth Preferably, the perforations throughthe tuenter when the hairs, such as L, go through, as

1 shown in Figs. 3 and 5, thus securing a close shave.

To put in place or to remove a blade for any purpose, such as cleaning, the guard T is unj screwed from the threads. It on hub l3 and, if

necessary, the cap C is also removed so that water or other device for cleaning can get at the inside I of the guard T.

To take care of the hair which is drawn in through the hair holes 4, 4, .I may have air vents or air outlets l1, l1 near the fixed end of guard T 1 or, as shown in Fig. 10, I can use a cap 80 in i which there are air vents 3|, 3|. I

- There is asingle blade 32 in slot 3|.

air in through the hair holes 23 andexpel it from the open end 23 of the guard T.

In Fig. 5, I show a blade holder 30 with a single slot 5|, the central plane of which extends directly through the axis of the blade holder.

This construction is ffective but it is more dimcult to balance the revolving parts and the faces at the forward edge of the blade 52, being at nearly ninety degrees with the inner surface of the guard, I

- 63, whereby the two blades 64, 64, each with slots 65, 35 can'be held in place by the heads of these pins. As the blade holder 30 revolves at a high rate of speed, centrifugal force throws these bular guard are of truncated conical form so that 5 the surface or skin of the human flesh K can As shown in Fig. 9, I can provide a power shaft 1 20, which may be from an electric or other motor 3 or from a flexible shaft, with a hub 21 to which i is screwed one-end of tubular guide 2| having hair holes 28 and with no vcap at its outer or free In this case, the blade holder '22 is provided with blade slots 23 at the inner end of each of which is preferably a recess 24 to receive a tail I24 at one end of a blade, such as 25. The outer end I23 of each slot 23 may be open and there is no bearing at the outer end I29 of blade holder 22, as it issufllciently held by hub 21'.

The open end 29 of the guard 2| takes the blades radially outward so that they run along the cylindrical inside surface of guard 31 I As shown in Flg. 8, in some places, such as barber shops, the drivingmeans carried by a housing 10 can be one end of aflexible shaft 1| which is directly connected to afixedshaft'12 carrying a blade holder 13 for a blade 14 inside a housing 15.

I claim:

1. The combination in-a power shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having perforations through the wall thereof, said perforations being of truncated conical form and each terminating in a relatively sharp edge at the inside of the guard; with a shaft. carried by the v housing and revoluble by the driving means; a cylindrical blade holder mounted on said shaft and revoluble inside the guard, said blade holder having a plurality of longitudinal slots arranged in planes which rake forward from the axis towards the direction of rotation; a removable cap carried at the free end of the guard and serving.

as a bearing for the shaft; and a plurality of cutting blades of rectangular form with a straight outer edge of greater length than the inside radius of the tubular guard and each slidable outwardly in a slot in the blade-holder.

2. The combination in a power shaving devicei of a housing carrying driving means and a tubular guard'flxed to the housing and having perforations through the wall thereof, said perforations each terminating in a relatively sharp edge at the inside of the guard; with a shaft carried by the housing and revoluble by the driving means; a cylindrical blade holder mounted on said shaft and revoluble inside the guard, said blade holder having a plurality of longitudinal slots arrangedin planes which rake forward from the axis towards the direction of rotation; a removable cap carried at the free end of the guard and serving as a bearing for the shaft; and a plurality of cutting blades of rectangular form with a straight outer edge of greater lengthjhan the inside radius of the tubular guard and each slidable outwardly in a slot in the blade holder.

3. The combination in a power shavingdevice;

'- of a housing carrying driving means and a tubular guard fixed tothe housing and having perforations through the wall thereof; with a shaft carried by the housing and revoluble by the driv-. ing means; a cylindrical blade holder mounted on said shaft and revoluble inside the guard, said blade holder having a plurality" of longitudinal slots arranged in planes which rake forward from the axis towards the direction of rotation; a removable cap carried at the free end of the guard and serving as a bearing for the shaft; and a plurality of cutting blades of rectangular form with a straight outer edge of greater length than the inside radius of the tubular guard and each slidable outwardly in a slot in the blade holder.

4. The combination in apower shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having perforations through the wall thereof; with a shaft carried by the housing and revoluble by the driving means; a blade holder mounted on said shaft and revoluble inside the guard, said blade holder having a plurality of longitudinal slots. arranged in planes which rake forward from the axis towards the direction of rotation; and a plurality of cutting blades of rectangular form with a straight outer edge of greater length than 1 the inside radius of the tubular guard and each slidable outwardly in a slot in the blade holder.

5. The combination in a power shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having tapered hair holes and an air vent through the wall thereof; with a shaft carried by the housing and revoluble by the driving means; a blade holder mounted on said shaft and revoluble inside the guard. said blade holder having a longitudinal plane surface extending in a substantially radial direction and'a fan blade proximate the air vent:

and a cutting blade of greater length than the inside radius of the tubular guard and slidable outwardly on such plane surface so as to engage the inner surface of the tubular guard.

8. The combinationin a power shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having hair holes and an air vent; with a shaft carried by thehousing and revoluble by the driving means; a blade holder mounted on said shaft and revoluble inside the guard, said blade holder having a longitudinal plane surface extending in a substantially radial direction and a fan blade;

and a cutting blade of greater length than the inside radius of the tubular guard and slidable outwardly on such plane surface so as to engage the inner surface of the tubular guard.

7. The combination in a power shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having perforations through its wall: with a blade holder revoluble inside the guard by the driving means, said blade holder having a longitudinal slot of greater leng than the inside radius of the tubular guard 11 which extends in a substantially radial direction outward from proximate the axis of rotation; and a cutting blade slidable outwardly in said slot.

8. The combination in a power shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having. perextends in a substantially radial direction outward from proximate the axis of rotation; and a cutting blade with a straight outer edge of greater length than the inside radius of the tubular guard and slidable outwardly along said guiding surface.

9. The combination in a, power shaving device;

of a housing and of a guard fixed to the-housing and having a cylindrical interior and perforations through its wall; with a blade holder revoluble inside theguard. said blade holder having a fiat longitudinal guiding surface which extends in forations extending entirely around and through a substantially radial direction outward from proximate the axis of rotation; a cuttingblade' with a straight outer edge of greater length than the inside radius of the tubular guard and slidable outwardly along said guiding surface; and

to overcome friction and to throw the cutting blade out by centrifugal force.

10. The combination in a power shaving de-.

vice; of a housing carrying driving means and a tubular guard fixed to the housing and having perforations through its wall; with a blade holder attached to and revoluble by the driving means and having a longitudinal slot with parallel side walls which extend longitudinally of the axis of the guard in a substantially radial direction outward from proximate said axis which is the axis of rotation; and acutting blade with parallel side walls, which blade fits the slot with a smooth, running fit, the blade being of greater length than the inside radius of the tubular guard and being slidable'outwardly in said slot.

11. The combination in a power shaving device; of a housing carrying driving means and a tubular guard fixed to the housing and having perforations through its wall; with a blade holder attached to and revoluble by the driving means and having a fiat longitudinal guiding surface which extends in a substantiallyradial direction outward from proximate the axis of the guard which is the axis of rotation; and a cutting blade with a straight outer edge which is parallel with said axis and is of greater length than the inside radius of the tubular guard, the blade being closely slidable outwardly along said guiding'surface.

12. A rotary razor including a motor,-a shaft 'extending from said motor, an enlarged extension on said shaft, longitudinally extending radial slots in said extension, razor blades loosely mounted in said slots, a fan-blade secured to the said shaft between the enlarged extension and the motor, and a tubular housing surrounding said shafts, razor blades and fan-blade.

13. In a rotary razor, a handle, a motor within the handle, a shaft extending from the motor, approximately radial slots in said shaft, blades slidably positioned within said slots. and a perforated tubular housing adapted to cover said shaft and blades. said tubular housing having a closed end provided with a bearing for supporting the end of the motor shaft.

' WILLIAM P. BOYD. 

